Currently, there are about 2,000 patients per year in the U.S. who need replacement tracheal tissue. Causes for this include tracheal cancer, invasive infections of the trachea or bronchi, and trauma. There are no replacements currently available for trachea in humans. At best, when a segment of trachea is resected, the only surgical option is to “pull together” the two ends of the trachea and sew them together, hoping that the anastomosis does not “pull apart” thereafter.
Currently in the U.S., approximately 4,000 patients per year need an esophageal replacement. This is due primarily to esophageal cancer, though trauma and infection are causes a small number of cases of esophageal replacement. Currently, there is no available replacement for esophageal tissue. What is done currently to replace esophagus is one of two procedures. Either a segment of the stomach is loosened from its connections in the abdomen and brought up into the chest, to anastomose to the remnant esophagus; or, a segment of large bowel (i.e., colon) is resected from the patient and sewn in to replace the resected esophageal tissue. Both of these procedures have many complications and a viable esophageal replacement is certainly medically needed.
Every year in the U.S., approximately 10,000 patients undergo cystectomy, and require a urinary conduit to drain urine outside the body [Healthcare Cost and Utilization Project, N.I.S., 2007.]. In almost all cases, bowel is harvested from the patient to form either a noncontinent urinary diversion, or a continent urinary diversion that is catheterized intermittently to drain urine through a continent stoma. [Konety, B. R., Joyce, G. E., Wise, M., Bladder and upper tract urothelial cancer. Journal of Urology, 2007. 177: p. 1636-1645.]. Due to surgical simplicity and lower complication rates, creation of a noncontinent urinary conduit is the most common approach for draining urine following cystectomy. Most typically, a 15-25 cm length of ileum is harvested from the patient for use as the urinary conduit, and the remaining bowel is reanastomosed [Gudjonsson, S., Davidsson, T., Mansson, W., Incontinent urinary diversion. BTU International, 2008. 102: p. 1320-1325.]. One end of the harvested ileal segment is anastomosed to the patient's ureters, and the other end is then brought out to the skin to form a stoma through which urine can drain.
Though widely used, ileal conduits pose many problems that can lead to short-term and long-term complications [Konety, Allareddy, V., Influence of post-cystectomy complications on cost and subsequent outcome. Journal of Urology, 2007. 177: 280-287.]. In the short term, patients may suffer from complications at the bowel harvest site, including anastomotic leaks and peritonitis. In addition, ileal urinary conduits may suffer from ischemia and necrosis, which can lead to perforation, anastomotic breakdown, and leakage of urine from the conduit. In the long term, many patients suffer from chronic hyperchloremic metabolic acidosis, due to resorption of urine electrolytes through the conduit wall. Since ileal conduits harbor bacteria, patients also commonly suffer from recurrent urinary tract infections and pyelonephritis, as bacteria from the conduit infect the more proximal urinary system. Hence, there is a significant medical need for an improved method for urinary diversion, that avoids many of the complications associated with the use of Heal conduits [Dahl, D. M., McDougall, W. S., Campbell-Walsh Urology, 9th Edition: Use of intestinal segments and urinary diversion, ed. A. J. Wein, Kavoussi, Novick, A. C. 2009].
There is a continuing need in the art tier replacements for these important conduits, as well as other tubular tissues in the body, such as ureters, urethras, intestine, etc.